.mask {
	position: absolute;
	top: 0;
	right: 0;
	bottom: 0;
	left: 0;
	color: #fff;
	font-size: 40px;
	text-align: center;
	line-height: 10em;
	background-color: #000;
	opacity: .8;
	z-index: 999;
}